diff --git a/content/client-server-api/_index.md b/content/client-server-api/_index.md
index c62938df..7cff2807 100644
--- a/content/client-server-api/_index.md
+++ b/content/client-server-api/_index.md
@@ -2621,6 +2621,8 @@ An example of the capability API's response for this capability is:
 
 ### `m.forget_forced_upon_leave` capability
 
+{{% added-in v="1.18" %}}
+
 This capability has a single flag, `enabled`, which indicates whether or
 not the server automatically forgets rooms which the user has left.
 
diff --git a/data/api/client-server/capabilities.yaml b/data/api/client-server/capabilities.yaml
index df86c2da..f73e8b46 100644
--- a/data/api/client-server/capabilities.yaml
+++ b/data/api/client-server/capabilities.yaml
@@ -51,6 +51,7 @@ paths:
                         $ref: '#/components/schemas/booleanCapability'
                         description: Capability to indicate if the user can change their password.
                       m.forget_forced_upon_leave:
+                        x-addedInMatrixVersion: "1.18"
                         $ref: '#/components/schemas/booleanCapability'
                         description: |-
                           Capability to indicate if the server automatically forgets rooms once the user